The boss of RBS has apologised for the recent IT meltdown that left millions of shoppers unable to pay for goods on the busiest shopping day of the year - Cyber Monday.
Ross McEwan, chief executive of the banking group, said decades of under-investment in the group's IT infrastructure had led to last year's IT glitches as well as the Cyber Monday issue.
He said: "[The] systems failure was unacceptable. [It] was a busy shopping day and far too many of our customers were let down, unable to make purchases and withdraw cash.
"For decades, RBS failed to invest properly in its systems. We need to put our customers' needs at the centre of all we do. It will take time, but we are investing heavily in building IT systems our customers can rely on.
"I'm sorry for the inconvenience we caused our customers. We know we have to do better. I will be outlining plans in the New Year for making RBS the bank that our customers and the UK need it to be. This will include an outline of where we intend to invest for the future."
RBS, NatWest and Ulster Bank customers were unable to make online and card payments for around three hours from 6.30pm on 2 December.
It echoed the IT issues experienced by RBS in 2012, when the same customers were locked out of their online banking facilities for days. RBS appeared to handle that crisis well, swiftly moving to communicate with and reassure customers.
It worked - NatWest won the Moneywise Customer Service Award for Most Trusted Mainstream bank in June 2013.
Unite, the union that represents staff at Royal Bank of Scotland, has called on the bank to halt its cost-cutting programme in light of yesterday's banking problems. Since 2008, RBS has announced over 30,000 job losses in the UK and Unite says it has embarked on extensive restructuring, including offshoring of IT functions.
Unite has today asked the bank to demonstrate these latest problems are not caused by staff shortages or a lack of necessary investment in the infrastructure of the bank.
Dominic Hook, Unite national officer, said: "IT problems will do nothing to reassure customers that RBS' commitment to quality customer service is backed up by proper investment in staff and systems.
"It is unacceptable that the bank's customers are once again facing inconvenience. Unite has grave concerns that staffing challenges are exacerbating the problems facing the bank, challenges that could be further amplified when the CEO announces the outcomes of his Strategic Review in February.
"RBS staff will now be working hard to rectify the problems at the bank. Serious questions must be asked as to why constant job cuts are being made when there are clearly serious issues which need addressing by management. Customers and staff have the right to expect more from their bank."